Conditions of the feet of animals, particularly ungulates, include such maladies as hairy heel warts, foot rot and foot scald and may present major health problems that can cause tremendous economic losses to producers of livestock. Lameness in cattle as a result of these conditions may result in loss of weight and body conditioning. In dairy cattle, milk production may be lowered because the animals may tend to go to feed less often. While conditions of the hoof are most prevalent in dairy cattle, beef cattle, goats and sheep, horses and other hoofed animals may be susceptible to the microbes which cause these conditions.
Papillomatous digital dermatitis (also known as Hairy Heel Warts), Footwarts and Strawberry Foot Diseases are inflammatory conditions which affect the skin around the hoof of an animal. These conditions commonly affect the back of the foot between the bulbs of the heels, but can spread around the foot and into the cleft between the claws. Digital dermatitis is a painful condition which may result in lameness, reduced food intake and fertility. Dairy cattle infected with the condition may also have reduced milk yields. Within a given herd, the proportion of animals affected by digital dermititis can remain at low levels of less than 10% while in others, over half of the animals of the herd can be affected. The severity of the condition may also vary according to location.
The precise cause of digital dermatitis is not known, but it is known that the condition is infectious in origin and that spiral bacteria are found in the lesions whereas they are not normally found in healthy skin. In fact, some strains of the condition are consistently found deep in damaged skin.
Foot rot, or infectious pododermatitis, is a hoof infection that is commonly found in cattle, sheep and goats. The condition rots away the foot of the animal, more specifically the area between the toes. Like digital dermatitis, foot rot is extremely painful and contagious.
In cattle, the cause of foot rot is thought to be one of two types of anaerobic bacteria, Fusobacterium necrophorum and Bacteroides melaminogenicus. Both types of bacteria are common in the environment in which cattle live. Fusobacterium is present in the rumen and fecal matter of cattle. Foot rot may also be caused by the microorganism Diechelobacter nodosus, which can be found in contaminated soil. Another cause of foot rot may include high temperatures or humidity, which may cause the skin between the hooves to crack and harbor infectious bacteria. Foot rot is prevalent in the southern region of the United States due to the wet and humid climate in that part of the country. If untreated, foot rot can spread to an adjacent joint, often resulting in the loss of the animal.
Foot scald, also known as benign foot rot or interdigital dermatitis, results in inflammation between the toes of an animal caused by the bacterium F. necrophorum. Persistent moisture on the skin between the toes can increase susceptibility to foot scald. which often precedes hoof rot. Like hoof rot, foot scald outbreaks occur most often during persistent rainy weather and high temperatures. If not treated, animals afflicted with foot scald may become permanently infected. As with other infectious conditions of the hoof, foot scald causes stress to the animals and can adversely affect weight gain, reproductive rates and production. Additionally, foot scald may incur additional costs to the livestock producer due to treatment and increased labor during an outbreak. Introducing an infected animal into an uninfected herd can create herd contamination and necessitate the treatment of all affected animals, including the previously-healthy ones, in the herd.
One method of treating foot, hoof, leg and other lesions in livestock and other animals includes preparation of an acidic antimicrobial footbath which may contain ions of an antimicrobial metal salt such as copper or zinc, for example, in an acidic solution such as aqueous sulfuric acid. The animals may be walked through the footbath at regular intervals such that the antimicrobial activity of the metal ions in the solution kills microbes which may otherwise cause or exacerbate the severity of lesions on the hoofs, feet and/or legs of the animals. The antimicrobial efficacy of the footbath solution requires complete or near complete dissolution of the metal ions in the solution. Dissolution of the metal ions to an extent which maintains their antimicrobial activity in the footbath solution requires that the solution be maintained at a pH of from about 1.0 to about 6.0 depending on the metal ion. Moreover, a pH increase above these levels causes the metal ions to precipitate out of solution and consequently, the antimicrobial properties of the footbath are reduced. In addition, the precipitated metal may accumulate in the soil to levels which are toxic to soil microbes and crops. Soil toxicity may slow decomposition of organic matter and nutrient cycling in soil and consequently, compromise soil production and fertility.
As the livestock or other animals are walked through the footbath as part of the treatment regimen, organic loads including feces from the livestock or animals often drop into the footbath, raising the pH of the footbath solution. Therefore, it may be necessary to provide an acid/base buffer in the bath solution to maintain the low pH of the solution and complete or near-complete dissolution of the metal ions in solution. Moreover, the presence of an acid/base buffer in the bath solution renders the solution compatible with human health and less irritating to skin and less corrosive to metals and concrete. In animals with healthy hooves, the formulation may help prevent digital dermatitis and interdigital phlegmon (foot rot) by maintaining healthy hoof conditions. The drying properties of the formulation may enhance hoof hardness and render soft tissue of hooves invulnerable to bacterial infection.
Accordingly, animal lesion treatment and prevention formulations and methods having enhanced acid/base buffering capability are needed.